It is difficult to get a sense of the scale of this massive Ziggurat which will be able to house 7 million people – more than some of the largest cities in the United States. When finished, this structure will essentially be a city unto itself – complete with public transportation running not only horizontally through it but also vertically. It is designed to be carbon-neutral and to draw much of its energy from an external grid of solar panels covering most of its exterior surface area. (Source)